INDIAN CORN. 165 



but keeps the water in the soil below the stirred por- 

 tion. If two inches of cut straw are spread upon the 

 surface of the soil, the evaporation will be checked 

 for obvious reasons. Two inches of pulverized soil 

 acts in much the same manner, although much less 

 effectively, as direct experiment has shown. Indeed, 

 the saving of moisture by surface culti\jation will de- 

 pend very largely upon the nature of the weather. If 

 this pulverized surface is frequently moistened by 

 rains, the evaporation from the stirred portion may be 

 greater than the evaporation that is thereby checked 

 from the soil below. On the other hand, if the sur- 

 face is kept loose more of the water which falls upon 

 it will pass into the soil and less will run off than 

 upon a hard surface. 



In any case the evaporation that is checked by the 

 stirring of the surface is small compared with the 

 quantity of water taken from the soil by an ordinary 

 growth of weeds. The killing of weeds is much more 

 important, therefore, in conserving moisture than is 

 stirring the soil. That this is true is indicated by 

 the fact that, on certain soils, at least, good crops of 

 corn can be raised without any stirring of the soil, 

 provided the land is kept thoroughly free of weeds. 



In ordinary practice it is essential to stir the soil in 

 order to kill the weeds. It may be laid down as a 

 rule, therefore, that the soil should not be stirred 

 deeper than is essential to a thorough eradication of 

 the weeds. There seems to be pretty good evidence 

 that the cultivation need not be more frequent than 

 is necessary for their complete destruction. 



Harvesting. — When the corn is grown for the 

 grain, it is not harvested until entirely ripe and 



